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Leaking blebs after trabeculectomy

Novel technique offers compelling approach to leaking blebs

Dermot McGrath

Posted: Sunday, November 1, 2020

A novel minimally invasive conjunctival surgical (MICS) technique may provide a safe, efficient and effective approach to the problem of leaking blebs after trabeculectomy surgery in glaucoma patients, according to Neeru Gupta MD, PhD.
“I have found this new approach extremely useful in my own practice. The outcomes have been very good, all of the leaks using this MICS approach were sealed almost immediately and patients were able to return to their regular activities very soon after surgery,” she said at the World Ophthalmology Congress 2020 Virtual.
Dr Gupta, professor and Dorothy Pitts Chair at the University of Toronto, Canada, explained that leaking filtration blebs are a common complication of trabeculectomy that can occur days, months or years after the initial surgery.
“A leaking bleb can lead to devastating problems such as blebitis and endophthalmitis. With a bleb leak there is also a reduction in IOP, leading to significant structural changes with shallowing of the anterior chamber, fluid build-up through the choroidals and the risk of hypotony maculopathy,” she said.
A wide variety of different approaches have been employed to try to manage bleb leaks after trabeculectomy surgery, said Dr Gupta.
“Conservative treatment is usually first-line treatment with antibiotics, reducing the frequency of topical steroids, or administering an aqueous suppressant. We can use a pressure patch to try to seal the leak. Other treatments such as bandage contact lens, collagen shields or cyanoacrylate tissue glue, which can lead to foreign body sensation and can be difficult to apply, have also been tried with limited success,” she said.
Other strategies to deal with a leaking bleb include argon or Nd:Yag laser treatment to try to seal the leak, or autologous blood patch injection into the bleb to stimulate fibrosis and promote scarring and healing.
Microsurgical techniques have also been tried with varying degrees of success, said Dr Gupta.
These approaches include re-suturing of the bleb for early postoperative period leaks, with excision of the bleb and conjunctival advancement followed by creation of a conjunctival pedicle flap that is sutured to the area and is typically used in cases of late-onset leakage. Other microsurgical techniques that have been tried include fascia lata grafts, corneal patch grafts, amniotic membrane, conjunctival graft, scleral patch graft and buccal mucosa transplant.
“All of these various techniques have had limited success, which explains why we continued to search for a more effective solution to the problem of a leaking bleb,” she said.
Dr Gupta’s solution was to come up with a minimally invasive conjunctival surgical procedure without tissue incision or excision which she said has proven very effective in patients with late-onset bleb leaks.
After injection of topical anaesthesia, a lid speculum is inserted to bring the superior avascular leaking bleb into view. The eye is then rotated downward to expose the superior bulbar conjunctiva behind the bleb and injected with subconjunctival lidocaine 2% with epinephrine. The superior bulbar conjunctiva behind the bleb is injected to balloon the conjunctival tissue which is then advanced over the thin bleb toward the limbus and sutured in place. The procedure is repeated in order to cover the entire area of the leak, with two-to-four sutures typically used to cover the leaking bleb.
Once the procedure has been completed, the conjunctival integrity and IOP are re-assessed at the slit lamp to check for bleb leak and prednisolone and antibiotics are administered for approximately one week, she said.
Dr Gupta has published her results in 14 eyes of 13 patients, 12 of whom had open-angle glaucoma and one iridocorneal endothelial syndrome (Am J Ophthalmol. 2019;207). The mean age of presentation was 70.2 years (± 14.8 years), and all patients had a history of mitomycin use at the time of glaucoma surgery. The onset of bleb leak following trabeculectomy ranged from seven months to 16.3 years. In all cases, the initially repaired filtering blebs remained functional at last follow-up, and no additional medications were required.
“The outcomes of this technique have been very good in this consecutive series of patients with all of the leaks sealed tight away and patients being able to return to their regular activities without any problem,” she said.
Dr Gupta said that the MICS procedure is particularly suited to dealing with classic focal avascular bleb close to the limbus that requires little tissue coverage from the conjunctiva above. However, it is not a viable option in patients with severe conjunctival scarring or in whom conjunctival mobilisation is impractical.
Summing up, Dr Gupta said that the MICS approach offers a relatively simple, economical and effective option for treating late-onset leaking blebs without cutting or excising conjunctival tissue.
“It is incision free with a good success rate. It is relatively simple, inexpensive and efficient and can be performed in a minor OR room, and the patient is able to resume their normal activities with minimal inconvenience,” she said.